Ivacaftor Use May Reduce Lung Infections in Patients with Cystic Fibrosis

Ivacaftor (Kalydeco) may help reduce respiratory infections over time in patients with cystic fibrosis (CF), according to a new study published in the Annals of the American Thoracic Society.

Patients whose CF is caused by a “gating” mutation, a group of mutations accounting for approximately 4% of all CF cases, are often prescribed ivacaftor, according to the study. Ivacaftor, a CF transmembrane conductance regulator (CFTR) potentiator, can restore CFTR function in patients with these mutations.

In addition to several other clinical benefits for patients with CF, a new study provides evidence that ivacaftor may also reduce some of the most common lung infections that occur with the disease, including P. aeruginosa. For the study, the researchers used data from a CF registry in the United Kingdom to compare patients with CF aged 6 years and older who received ivacaftor with those who did not take the drug over a 3-year period.

According to the data, the researchers determined that ivacaftor use was associated with early and sustained reductions in positive respiratory cultures for P. aeruginosa, resulting in a 32% decrease in likelihood of infection after 3 years of treatment. Patients who took ivacaftor also experienced a 15% reduction in Staphylococcus aureus. These reductions resulted from both increased clearance in those already infected and in reduced acquisition in those not affected, the researchers noted.

The drug was also associated with reduced Aspergillus spp. infections but did not appear to reduce Burkholderia cepacian complex infections, according to the study.

“People with CF notice improvement in lung function and quality of life soon after they start taking ivacaftor, but they still have to live with a considerable treatment burden from all the other medications they take,” lead author Freddy Frost, BMBS, a CF physician at Liverpool Heart & Chest Hospital, said in a press release. “At present, we simply don’t know whether it’s safe to stop some of those other treatments. The fact we have seen reduced infections in this study suggests there may be some people who can safely discontinue medications targeted towards those infections.”

According to the results, one-third of patients with chronic P. aeruginosa infection prior to ivacaftor initiation had a negative culture at the end of the study period. Given the morbidity associated with chronic infection, these findings have important clinical implications for patients with CF and could potentially reduce the need for aggressive antibiotic therapy.

“As some people with CF remain clinically stable having received over 5 years of ivacaftor therapy, understanding the long-term microbiological consequences becomes increasingly important for predicting future morbidity and also in implementing antibiotic stewardship,” the researchers wrote in the study.

Further research will be needed to determine whether it is safe to reduce the overall treatment burden of CF by decreasing antibiotic use in these patients, they concluded.

Reference

Frost FJ, Nazareth DS, Charman SC, et al. Ivacaftor is associated with reduced lung infection by key cystic fibrosis pathogens: A cohort study using national registry data. Annals of the American Thoracic Society. 2019. http://www.thoracic.org/about/newsroom/press-releases/conference/2019/201902-122OC.pdf